Z86E30/E31/E40
Z8 4K OTP Microcontroller
Zilog
FUNCTIONAL DESCRIPTION
The MCU incorporates the following special functions to
enhance the standard Z8 architecture to provide the user
with increased design flexibility.
Note: The device V must rise up to the operating V
CC CC
specification before the TPOR expires.
Program Memory. The MCU can address up to 4 KB of
Internal Program Memory (Figure 22). The first 12 bytes of
program memory are reserved for the interrupt vectors.
These locations contain six 16-bit vectors that correspond
to the six available interrupts. For EPROM mode, byte 12
(000CH) to address 4095 (0FFFH) consists of program-
mable EPROM. After reset, the program counter points at
the address 000CH, which is the starting address of the
user program.
RESET. The device is reset in one of three ways:
1. Power-On Reset
2. Watch-Dog Timer
3. STOP-Mode Recovery Source
Note: Having the Auto Power-on Reset circuitry built-in,
the MCU does not need to be connected to an external
power-on reset circuit. The reset time is 5 ms (typical). The
MCU does not re-initialize WDTMR, SMR, P2M, and P3M
registers to their reset values on a STOP-Mode Recovery
operation.
In ROMless mode, the Z86E40 can address up to 64 KB
of External Program Memory. The ROM/ROMless option
is only available on the 44-pin devices.
EPROM
65535
ROMless
External
ROM and RAM
4096
External
ROM and RAM
4095
On-Chip One Time PROM
Location of
First Byte of
Instruction
Executed
After RESET
12
11
10
9
IRQ5
IRQ5
IRQ4
IRQ4
IRQ3
IRQ3
IRQ2
IRQ2
IRQ1
IRQ1
IRQ0
IRQ0
IRQ5
IRQ5
IRQ4
IRQ4
IRQ3
IRQ3
IRQ2
IRQ2
IRQ1
IRQ1
IRQ0
IRQ0
8
7
Interrupt
Vector
(Lower Byte)
6
5
4
Interrupt
Vector
(Upper Byte)
3
2
1
0
Figure 22. Program Memory Map
(ROMless Z86E40 Only)
32
P R E L I M I N A R Y
DS97Z8X0500
ZILOG [ ZILOG, INC. ]
